1. Field of the Invention
The present invention relates generally to methods of performing periodontal surgeries, and instruments for performing said surgeries.
2. Related Art
Gum diseases, such as periodontitis and gingivitis, can cause damages to the gum near the root of a tooth. In some cases, the gum line near a tooth can recede, exposing the root of the tooth in a condition known gingival recession. The receded gum line is called a gingival defect. The gingival defect of a receding gum near the root of a tooth is unsightly, can cause discomfort, and can lead to severe damages to the gum and tooth.
When a gingival defect becomes severe, it is sometimes necessary to use periodontal surgeries to correct this defect. There are several conventional methods of performing gingival defect correction surgeries (also known as gingival augmentation surgeries).
A common approach (for root coverage) involves making large incisions and grafting tissues to the gum to cover the gingival defect. First, a horizontal incision is made along the gum line where the gum comes into contact with the teeth (also known as the gingival margin). This horizontal incision is made around the effected tooth or group of teeth and the immediately adjacent teeth. Next, two vertical incisions, along the length direction of the teeth, are made at the two ends of the horizontal incision. The vertical incisions are made from the horizontal incision to the muco-gingival junction.
Next, a flap is created by peeling open the region of gum defined by the horizontal and vertical incisions, either in the upward direction for surgeries on the an upper tooth, or in the downward direction for a lower tooth, thus exposing the underlying bone. Then new tissues are grafted under the flap onto existing tissues. The new grafted tissues can come from the patient's own palate tissues, or from donor or animal tissues.
After the grafting of new tissues, the flap is closed down onto the grafted tissues, and the incisions are closed using multiple sutures.
While this surgery technique is capable of repairing gingival defects for one tooth or a group of adjacent teeth, it is a complicated surgery with a relatively long recovery time and significant morbidity. The outcome of the surgery is technique sensitive—the surgery is subject to failure from errors made by even well-trained surgeons or operators. Also, the incision area is large, which increases the recovery time and increases the possibility of an infection. Lastly, due to the large incisions made during the surgery and the grafting of new tissues, it is likely that the patient will have visible permanent scars on the gum tissues resulting from the surgery. In addition, the grafted tissue often does not match with the patient's own tissues in color and appearance, which may further create an unaesthetic appearance for the patient.
A second and less invasive surgery technique is also available to correct minor gingival defects. First, a small incision is made approximately 2-3 mm away from the receded gum line. Another incision is made at the gum line. A split-thickness dissection (operation to delicately “fillet” the inner side of the flap) is then performed. If not properly done, this dissection procedure can lead to a loss of blood supply and necrosis of the flap. When dissection is completed, this thinned out flap of gingival tissue is collapsed into the defect and held for a few minutes. Suturing is generally not necessary.
While this surgery technique is less invasive compared to the previous technique, there are several disadvantages. First, because part of the gum is moved to cover the gingival defect, this leaves a gap at the point of incision. This gap can expose part of the root of the tooth and may lead to other complications. Secondly, this technique allows at most a movement of the gum line for up to 3 millimeters (mm), and is not available for more severe gingival defects where the gum line recedes more. Further, this technique can be used to repair gingival defect for only one tooth at a time, not a group of teeth. Hence, each tooth with a gingival defect requires a separate incision. Like the previous technique, this technique can also leave unsightly permanent scars on the gum of the patient. Lastly, this technique is not recommended for operations on lower teeth.
The above-described surgical methods are typically executed using conventional instruments. The design of these instruments, in terms of size, blade design, angulations of connectors and other characteristics, require extensive incisions and intricate suturing techniques. These instruments are not designed for minimally invasive gingival or papillae augmentation surgeries. For example, a “Goldman Knife” is an angled dental surgery instrument, with a shaft, a curved connector section connecting to the shaft, and a protruding blade section, wherein the blade has a cutting surface perpendicular to the length direction of the connector section immediately connecting to it. Because this instrument and other conventional instruments are not designed in particular to be used for gingival or papillae augmentation surgeries, the use of these instruments require large incisions and awkward operating angles for the surgeon, increasing the recovery time for the patient and decreasing the success rate of the surgeries.
Therefore, because of the disadvantages and limitations of the conventional surgical methods described above, it is highly desirable to have a surgical method which enables the efficient correction of severe gingival defects of varying degrees with one minimally invasive incision. A minimally invasive technique can minimize bleeding, swelling, and other post operative symptoms. Furthermore, a technique that does not interrupt the blood supply from gingival and mucosal tissues promotes rapid healing and minimize chances of infection. In addition, a technique that requires no suturing of soft tissues saves the surgeon operating time and minimizes tissue trauma and patient discomfort. Also, a method that is not “technique sensitive”, requiring no complex flap design and intricate suturing techniques, increases the success rate of the operation. It is also highly desirable to have a method that is effective in all four quadrants of the mouth, and applicable to large gingival defects, such as defects with recession of 7 mm or more in Miller I and II situations. Lastly, it is highly desirable to have a method that is cosmetically ideal and requires no tissue matching. In addition, it is also highly desirable to have instruments designed especially for performing gingival defect correction surgeries (gingival or papillae augmentation surgeries) with the characteristics described above to minimize the incision size and increase the surgeon's or operator's efficiency and success rate.